Darth Bane, born under the name of Dessel, was the Sith'ari and the Dark Lord of the Sith responsible for creating the Rule of Two. Born in 1,026 BBY, he was raised as a poor miner on the Outer Rim planet Apatros. After killing a Galactic Republic ensign in a fight in 1,003 BBY, Dessel was in danger of being arrested and imprisoned by the Republic. With the help of his friend Groshik, he escaped off-world to join the Sith Brotherhood of Darkness. Initially serving as a foot soldier in the Gloom Walkers unit, he was recognized as a Force-sensitive, and taken to the Sith Academy on Korriban.

Bane, as he had been christened, quickly became one of the best students at the Academy before he lost his faith in the dark side of the Force. Though Bane was able to regain his confidence in the dark side, he lost his trust in the Brotherhood of Darkness, believing it to be a flawed organization whose leader, Kaan, was a coward and a fool. Deserting the order, Bane studied the holocron of Darth Revan, and, armed with new knowledge, helped destroy the Brotherhood, allowing him to create his own Sith Order. He then instituted a Rule of Two, which stated that there could be only two Sith to avoid the infighting that had plagued the Sith for millennia. He also took both the title of Darth and an apprentice named Darth Zannah.

In 990 BBY, ten years after the destruction of the Brotherhood, Bane sought to learn how to create a holocron, through which he would pass down his knowledge to future Sith Lords. The Sith journeyed to the Deep Core world of Tython to locate the Sith holocron of the ancient Dark Lord Belia Darzu. However, while Bane was on Tython, the Jedi Order learned of his existence, and sent a group of Jedi to kill him and his apprentice. Once the Jedi arrived, they confronted the two Sith in Darzu's fortress. Though outnumbered, the Sith were able to defeat the Jedi; however, Bane was grievously injured. Zannah took him to Ambria, where she convinced the healer Caleb to help them. Caleb notified the Jedi Council, only to have Zannah use her powers to drive Caleb's assistant Darovit insane. Zannah killed Caleb, then hid herself and Bane. When the Jedi arrived, they killed Darovit, believing him to be the Sith Lord. Thus, the Sith were believed destroyed.

A decade later, Bane began to worry that his apprentice was too weak to overthrow him and assume the mantle of Dark Lord of the Sith, as was necessary under the Rule of Two. He began to research the secrets to prolonging his life by transferring his essence to another body, and traveled to Prakith, where he claimed the holocron of the ancient Darth Andeddu. After returning from Prakith, Bane was ambushed by a team of assassins hired by Caleb's daughter, Serra, and was captured. Taken to Doan, Bane was imprisoned and interrogated, only to covertly gain his freedom soon afterward. Encountering Zannah on Doan, Bane dueled his apprentice, who sought to become the new Dark Lord. The fight ended in a draw, with Bane escaping and heading to Ambria with Darth Cognus, an Iktotchi assassin skilled in use of the dark side who Bane planned to take as his apprentice if Zannah proved herself weak and unworthy. There, Bane and Zannah engaged in a fateful duel that resulted in the death of the Sith'ari and Zannah claiming the title of Dark Lord. Nearly a millennium later, Bane's Sith Order defeated the Jedi Order and overthrew the Republic.

Darth Andeddu, also referred to as the Immortal God-King of Prakith, was an ancient humanoid male who reigned as Dark Lord of the Sith, and was dubiously thought of as the forebear of the "Darth" title. A paranoid man, Andeddu believed that his subordinate Sith Lords—whom he regarded as his enemies—wanted to claim his vast collection of Sith lore and ritual for themselves. He was eventually betrayed and overthrown by his followers, forcing him to flee the planet Korriban for the Deep Core. Andeddu made the world of Prakith his domain where he ruled for centuries as a deity until his physical demise, at which time he entombed himself in an attempt to deprive his pursuers of the power they sought to steal. Prior to his physical death, Andeddu stored all of his wisdom within a holocron which also contained his most arcane secret: the ability to cheat death by transferring one's essence into another vessel. A Sith cult founded by Lord Andeddu called the "Malevolence" constructed a temple in reverence of their Dark Lord, and guarded the fortress for generations in anticipation of the God-King's return.

The legend of Darth Andeddu and his incredible powers remained at large long after his death, and the Jedi Order even attempted to erase all knowledge and reference of the Dark Lord from galactic record. Despite their best efforts, whispers of Andeddu's existence still remained prevalent. His holocron survived as well—first uncovered by the Sith Lord Darth Bane on Prakith in 980 BBY, then rediscovered by Darth Tyranus on Korriban in 21 BBY, and later recovered by Darth Krayt and his One Sith Order more than a century later. Krayt, who suffered from a Yuuzhan Vong slave seed infestation that threatened to leave him bereft of sentience, allowed his lieutenant Darth Wyyrlok III to access Andeddu's holocron in search of possible solutions. The device led the Chagrian Sith on a journey to Andeddu's Keep on Prakith, where he encountered and defeated the Malevolence cultists, but in doing so, he revived the ancient body of Darth Andeddu. The Dark Lord then dueled Wyyrlok on a battlefield of the mind, a contest which ultimately resulted in Andeddu's demise. His corpse was resealed within the tomb that had housed it for countless millennia, and his collection of Sith doctrines was pillaged by Wyyrlok, who hoped to obtain a viable means of ending Darth Krayt's plight.